What process describes the microbial uptake of mineral nitrogen from soil?

The process that describes the microbial uptake of mineral nitrogen from soil is immobilization. During immobilization, microorganisms utilize inorganic nitrogen, such as ammonium or nitrate, to synthesize organic nitrogen compounds. This process is crucial for soil nutrient cycling, as it converts mineral nitrogen—which is readily available for plant uptake—into organic forms that are temporarily locked within the microbial biomass.

Microorganisms absorb the mineral nitrogen from the soil, effectively reducing the levels of inorganic nitrogen available for plants. This means that while the nitrogen is essential for plant growth, some of it is taken up by microbes and not immediately available to plants. This uptake plays a significant role in maintaining nitrogen availability in the soil, as microbial biomass can eventually decompose, releasing nitrogen back into the soil in a form that plants can utilize.

The other processes listed have different functions related to nitrogen cycling. Ammonification refers to the conversion of organic nitrogen into ammonia, while denitrification is the reduction of nitrates back to nitrogen gas, releasing it into the atmosphere. Nitrification involves the oxidation of ammonia to nitrite and then to nitrate. Each of these processes contributes to the nitrogen cycle but does not specifically refer to the microbial uptake of mineral nitrogen.